Questions tagged [functions]

Questions about the use of built-in Mathematica functions, including pure functions.

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47 views

How to create a global function? [closed]

I am wondering how to create a global function. I want to build a function that will persist even when Mathematica's kernel is aborted and closed and eventually restarted. I think the answer has ...
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54 views

How to sort functions based on the number of arguments they take? [closed]

How can I find all functions with a certain number of arguments? For example, how can I find all the functions who do not require an argument like RandomReal[]? How can I find all the function that ...
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48 views

how to find the FWHM of a peak from an equation and not data set? [closed]

I want to find the FWHM of a conductance peak I created on mathematica (see Figure). until now I used the FindMaximum to calculate the max of the peak. ...
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43 views

How to get a list of all the Resource Functions on the Wolfram Function Repository? [duplicate]

I would like to find a way to get the name of every single ResourceFunction published on the Wolfram Function Repository. How can I find the names of every single function?
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1answer
36 views

How to define a matrix of functions that taking given letters as variable without giving specific expressions? [closed]

I have a vector defined by coord = {r, \[Theta], \[Phi], t}. Now I want to create a matrix of functions taking these $r,\theta,\phi,t$ as variables without giving ...
3
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1answer
86 views

What is the difference between Catenate and Flatten? [closed]

I am having a hard time understanding the difference between Flatten and Catenate. Consider the following example code: ...
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1answer
77 views

Solving a system of coupled trigonometric equations to find angles

I have a system of 9 coupled trigonometric equations (a 3X3 Matrix). I am trying to find four unknown angles $\theta_1, \theta_2, \phi_1, \phi_2$ by solving any 4 out of 9 such equations. $\text{M}=\...
2
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2answers
186 views

Defining a function recursively

I want to construct polynomials (or just function) $f_n$ from $f_{n-1}$ using mathematica. For some kind of reason, I didn't manage to do this. So basically something like a recurrence table, but for ...
2
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2answers
80 views

Problems with TagSet

I am new with TagSet and TagSetDelayed and I'm not understanding properly how they works. I introduced the following definition: ...
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2answers
63 views

Why the animation of a function gives different results from the integral?

My function is: A1[B_, x_, t_] := (AiryAi[B*(x - (B^3*t^2)/4)])^2 (B is a constant) and if I use "Manipulate" : ...
2
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2answers
51 views

Partially Orderless Arguments in Functions

I am a Mathematica beginner and I'm trying to implement a function of type f[i1_,i2_,i3_,i4_] such that it is orderless in the first two arguments and in the last ...
0
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1answer
57 views

NBodySimulation softening parameter

I'm simulating the orbit of a binary black hole immersed in some halo of particles and the simulation does not want to continue on for the specified amount of time. It always halts at a seemingly ...
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1answer
56 views

How to find all functions that accept level specifications as an argument?

How can I find a list of every function that takes a level specification as an argument?
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1answer
43 views

Integrate and InverseFunction

I solve an easy example to check that Mathematica can understand the difference between ArcTan and ArcTanh but as you see here I can't get Arctanh??!! Even I don't know why the inverse function is not ...
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0answers
47 views

Loops Not Working- Kernel Crashes and Values Incorrectly Updated

I haven't used Mathematica in a while so any help is very greatly appreciated. I am trying to run a program with nested for loops that runs two function evaluations in the inner most part of the loops....
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1answer
31 views

I have a variable error and was curious to see if it's due to piecewise functions?

So I have a displacement function sigx as a function of "t" (time) and sig.pre (pre-stress). At some time "dx": force "fo" goes to 0, and the same displacement function ...
2
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1answer
109 views

Biot-Savart Integral

I want to calculate the magnetic field of a finite wire of current along the z axis. I assume a frame of reference like the one in Fig. below: It is a classical problem with a well known solution for ...
1
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1answer
37 views

Simplify function with condition not working [duplicate]

I try to simplify the function Q below: Q[x_] := Sign[x] /; x > 1 Simplify[Q[x], Assumptions -> x > 1] (*return Q[x]*) But it doesn't work. However, if I ...
2
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2answers
79 views

Calculation of composite integrals

I am facing trouble calulating the following integrals. Could you give me any advice? My code is the following: ...
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0answers
42 views

Silly trouble expressing recursive formulas?

I am trying to code the following formulas: I did it in the following way: ...
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0answers
40 views

NIntegrate seems to not recognize multiplication of Piecewise function and f[t_]:= function, Why?

Considering inputs: vti={0, 1.5, 2.4, 5.0675, 7.735, 10}; Vscc=1.5; PSA=0.025; f=0.6; m=10; I defined a function "pwtemp2", using "FC1" and &...
4
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2answers
309 views

Mean of boolean list

In python I'm used to doing something like np.mean([True, False, True......]) to compute the fraction of True values in a list. ...
0
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1answer
98 views

Matching a Dynamic Argument Pattern

times is a list of times i.e. matching {{hour_, min_, sec_Real}..}. I want to call ...
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1answer
99 views

general replacement

I have 500 terms. and I want replace them with below function ...
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0answers
22 views

Adaptation of existing code to multivariable system

I am trying to adapt the existing code from "Mathematica package for analysis and control of chaos in nonlinear system" by Gutierrez. This existing code calculates the Lyapunov Exponent by ...
1
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0answers
60 views

Big O notation - Strange result [closed]

I tried to use the big O function in Mathematica, but I got a strange result. It should be different because the two terms should remain. ...
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0answers
67 views

Can't create matrix function of symbolic functions and assign values to elements

So I have a problem regarding the symbolic matrix value assignment. Say I create a matrix function as: P[t_]:= {{P1[t]}, {P2[t]}, {P3[t]}}; Then I want to assign ...
6
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1answer
78 views

unexpected StringCases behaviour inside function module

First, Let use see a = {"wx", "wy", "wz"}; AssociationThread[Flatten[StringCases[a, "w" ~~ d_ :> d]] -> a] gives <...
0
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1answer
48 views

Could anyone help me to plot the following function? [closed]

Unfortunately Mathematica is not able to run the following program area[d_]:=Pi*d^2/4 Q=80/1000 v[d_]:=Q/area[d] [Nu]=10^-6 Reynolds[d_]:=v[d]*d/[Nu] [Epsilon]=0.04/1000 CW[[Lambda],d]:=1/Sqrt[[Lambda]...
2
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1answer
70 views

How to make an interactive solver function?

I am working on creating a function that takes in any physics equation as a string and converts it to an equation that I will then paste into an interactive interface as asked here: How to make an ...
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0answers
20 views

(Laplace Coefficents) Integral function definition

TLDR: need help defining two functions involving integrals in the form of "Laplace Coefficents". My intention is to define functions that involve Laplace Coefficents. In particular, if $$b_{...
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0answers
29 views

Suppressing tensor indices and function labels of a function

I am trying to do some GR calculations, and want to write a code which shows the expressions symbolically using compact indices, rather than write all the quantities in detail. More precisely, ...
0
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2answers
52 views

How to use NSolve while specifying the range of one variable

I have an equation that uses three variables that I have defined as follows: b[l_, m_, lt_] := 0.025 * (((1 - m)*l)^(-1/2))*((1 - m)*lt) - 5. After this definition, ...
3
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1answer
94 views

What's the meaning of Sign function applied to matrices with MatrixFunction?

I have noticed that Sign function can be very well applied to matrices using MatrixFunction. It even works on some zero divisors,...
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0answers
72 views

Multivariate Pade approximant

Does Mathematica generate multivariate or just two-variate Pade approximant? If so, what is the generating command?
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38 views

Create a function from another by substituting arguments

Suppose I have a function f[x, coeff] ...
2
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0answers
36 views

Can't match custom head in function signature [closed]

I have written a financial charting function which has the following signature; ...
0
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1answer
31 views

Setting rules for Gamma functions

I have some expressions involving lots of Gamma functions. Now the arguments of the functions sometime go to zero, in which case I want to use the factorial instead of the Gamma function (since it ...
11
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1answer
707 views

How to make a haunting ghost?

How to make a harmless ghost (one that looks like a flying bed sheet)? One can always make a Ghost Curve. Or one can define define a clever wiggly function with a random fluctuation. My initial guess ...
3
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1answer
39 views

What is the precedence or order of operation for multiple functions applied to a dataset?

This is from the Wolfram Language book section 45 on the planets dataset. This works: ...
2
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1answer
62 views

How to manipulate functions?

This is probably a simple question, I have matrix a , and I construct b from a by adding a variable to the first column. b is a function of variable d, and now I need to do mathematical calculation on ...
-3
votes
1answer
50 views

Maximize function problem [closed]

I don't understand why I'm getting no solution with the Maximize function in this case: while it returns the right result when I impose $y\leq0.999$ (or, equivalently, $x\leq0.999$):
1
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1answer
50 views

How i can add an element of one sublist to other?

I have list. st = {{1, 2, 3}, {}, {}} It is nessesary to add the first element of any sublist to start of other sublist. In a quick way. Example: from 1 to 2 ...
0
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2answers
78 views

NMaximize - global maximum fail - How to?

Problem : Let x,y,z be non-negative real number whose sum is 1. Find maximum of 0.2x + 0.2y + x^2*z + y*z^2 What I did first was reducing variable. ...
0
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1answer
54 views

Asymptotic bode plot [closed]

Is it possible to plot an asymptotic bode plot. I am interested in verifying my straight line bode plot approximations done by hand by using mathematica but the bodeplot function generates the curved ...
0
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0answers
43 views

How to define the normalized spacing?

I want to write the formula for normalized spacing in Mathematica and I want to use it in rest of the problem. To write the formula $D=(n-i+1)(x_{(i)}-x_{(i-1)})$ I wrote the following function. ...
0
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0answers
63 views

Ising Model 1D /Thermodynamics properties

I want to plot the thermodynamics properties of the Ising model like free energy, entropy, magnetization..etc., when h=0 ( no external field ) and when h= finite values For the energy as function of ...
2
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1answer
108 views

How to expand a function as a linear combination of other functions?

I would like to be able to expand certain functions as linear combinations of other specified functions when I know that the original function can be represented in such a way e.g. we know that $\sin^{...
1
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0answers
63 views

Does Mathematica assume real variables in this case?

When we have a function like $f(x) = x^2-1$ and we expand it in a power series about some $x = x_0$, does Mathematica automatically assume that $x$ is real valued?

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